[PATCH] D58192: [LoopUnrollPeel] Add case where we should forget the peeled loop from SCEV.

[Florian Hahn via Phabricator via llvm-commits]

fhahn updated this revision to Diff 186827.
fhahn added a comment.

Use forgetTopmostLoop and get rid of getting the parent loop, as it is not
required any longer.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D58192/new/

https://reviews.llvm.org/D58192

Files:
  llvm/lib/Transforms/Utils/LoopUnrollPeel.cpp
  llvm/test/Transforms/LoopUnroll/peel-loop-scev-invalidate.ll


Index: llvm/test/Transforms/LoopUnroll/peel-loop-scev-invalidate.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/LoopUnroll/peel-loop-scev-invalidate.ll
@@ -0,0 +1,42 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -S -loop-unroll -unroll-force-peel-count=1 -verify-scev -verify-dom-info | FileCheck %s
+
+
+define void @test1(i32 %k) {
+; CHECK-LABEL: @test1(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[FOR_BODY_PEEL_BEGIN:%.*]]
+; CHECK:       for.body.peel.begin:
+; CHECK-NEXT:    br label [[FOR_BODY_PEEL:%.*]]
+; CHECK:       for.body.peel:
+; CHECK-NEXT:    [[INC_PEEL:%.*]] = add nsw i32 0, 1
+; CHECK-NEXT:    [[CMP_PEEL:%.*]] = icmp ult i32 0, [[K:%.*]]
+; CHECK-NEXT:    br i1 [[CMP_PEEL]], label [[FOR_BODY_PEEL_NEXT:%.*]], label [[FOR_END:%.*]]
+; CHECK:       for.body.peel.next:
+; CHECK-NEXT:    br label [[FOR_BODY_PEEL_NEXT1:%.*]]
+; CHECK:       for.body.peel.next1:
+; CHECK-NEXT:    br label [[ENTRY_PEEL_NEWPH:%.*]]
+; CHECK:       entry.peel.newph:
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[I_05:%.*]] = phi i32 [ [[INC_PEEL]], [[ENTRY_PEEL_NEWPH]] ], [ [[INC:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT:    [[INC]] = add nuw nsw i32 [[I_05]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i32 [[I_05]], [[K]]
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[FOR_END_LOOPEXIT:%.*]], !llvm.loop !0
+; CHECK:       for.end.loopexit:
+; CHECK-NEXT:    br label [[FOR_END]]
+; CHECK:       for.end:
+; CHECK-NEXT:    ret void
+;
+entry:
+  br label %for.body
+
+for.body:
+  %i.05 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+  %inc = add nsw i32 %i.05, 1
+  %cmp = icmp ult i32 %i.05, %k
+  br i1 %cmp, label %for.body, label %for.end
+
+for.end:
+  ret void
+}
Index: llvm/lib/Transforms/Utils/LoopUnrollPeel.cpp
===================================================================
--- llvm/lib/Transforms/Utils/LoopUnrollPeel.cpp
+++ llvm/lib/Transforms/Utils/LoopUnrollPeel.cpp
@@ -664,16 +664,11 @@
     LatchBR->setMetadata(LLVMContext::MD_prof, WeightNode);
   }
 
-  // If the loop is nested, we changed the parent loop, update SE.
-  if (Loop *ParentLoop = L->getParentLoop()) {
-    SE->forgetLoop(ParentLoop);
-
-    // FIXME: Incrementally update loop-simplify
-    simplifyLoop(ParentLoop, DT, LI, SE, AC, PreserveLCSSA);
-  } else {
-    // FIXME: Incrementally update loop-simplify
-    simplifyLoop(L, DT, LI, SE, AC, PreserveLCSSA);
-  }
+  // We modified the loop, update SE.
+  SE->forgetTopmostLoop(L);
+
+  // FIXME: Incrementally update loop-simplify
+  simplifyLoop(L, DT, LI, SE, AC, PreserveLCSSA);
 
   NumPeeled++;
 


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